State Highway 2 north of Wellington is closed after a crash and drivers should expect long delays.
Police said the collision between two vehicles was reported just after midday in Kaitoke between Kaitoke Loop Road and Gilbert Road.
Motorists are being asked to avoid the area as there is no detour available.
A person at the scene said it appeared a car was pulling out of a driveway and was hit by another vehicle.
A person was trapped in the wreckage, he said.